Phosphate ester additives for low foam nonionics

ABSTRACT

ORGANIC PHOSPHATE ESTER ADDITIVES, WHEN BLENDED WITH LOW FOAM MONIONIC COMPOUNDS, SUPPRESS FOAM GENERATED BY PROTEINACEOUS SOIL ON PARTICULES BEING CLEANED. THE ESTERS ARE PRODUCED BY PHOSPHORYLATION OF C16 TO C20 ALCOHOLS, THE 1-MOLE ETHYLENE OXIDE ADDUCT OF 16 TO 20 CARBON ALCOHOLS, THEIR BLENDS, AN ALCOHOL-1-MOLE ETHOXYLATE MIXTURE, OR A BLEND OF ETHYLENE OXIDE ADDUCTS OF A C16 TO C20 ALCOHOL WHEREIN THE 1-MOLE ADDUCT IS OPTIMIZED.

United States Patent O 3,595,968 PHOSPHATE ESTER ADDITIVES FOR LOW FOAM NONIONICS William L. Groves, Jr., Ponca City, Okla, assignor to Continental Oil Company, Ponca City, Okla. No Drawing. Filed June 9, 1969, Ser. No. 831,718 Int. Cl. B01d 19/04; Clld 3/36, 7/48 US. Cl. 252-99 2 Claims ABSTRACT OF THE DISCLOSURE Organic phosphate ester additives, when blended with low foam nonionic compounds, suppress foam generated by proteinaceous soil on particules being cleaned. The esters are produced by phosphorylation of C to C alcohols, the l-mole ethylene oxide adduct of 16 to 20 carbon alcohols, their blends, an alcohol-l-mole ethoXylate mixture, or a blend of ethylene oxide adducts of a C to C alcohol wherein the l-mole adduct is optimized.

BACKGROUND OF THE INVENTION Field of the invention Brief description of the prior art The washing of dishes heavily loaded with proteinaceous soil in automatic dishwashing machines has been a problem facing consumers and the surfactant industry for many years. The popularity of the automatic dishwashing machine, coupled with the trend toward the use of lower water temperatures in such machines, has created problems as to excessive foaming of the detergent composition in such automatic dishwashing machines. This undesirable feature of many of the present commercial automatic dishwashing machine detergents is especially noticeable in the presence of raw egg soil. Development of excessive foam in the dishwashing machine can result in overflow of the machine. Even moderate foaming in the dishwashing machine reduces the efficiency of the automatic dishwashing machine by retarding the mechanical action of the water spray and by reducing the rate of rotation of the spray arms. Therefore, new low foaming detergent compositions and foam suppressant additives are constantly being sought for incorporation into detergent compositions and thus provide a detergent composition suitable for use in automatic dishwashing machines which does not foam excessively in the presence of proteinaceous soil, such as raw egg soil.

OBJECTS OF THE. INVENTION An object of this invention is to provide a low foaming detergent composition especially suitable for use in automatic dishwashing machines. Another object of the invention is to produce a detergent composition for use in automatic dishwashing machines which does not foam excessively in the presence of proteinaceous soil. Still another object of the invention is to provide an additive composition which, when formulated into a detergent composition suitable for use in an automatic dishwashing machine, will suppress foam generated by proteinaceous soil on articles being cleaned. These and other objects,

3,595,968 Patented July 27, 1971 advantages, and features of the present invention will become apparent to those skilled in the art from a reading of the following detailed description and appended claims.

SUMMARY OF THE INVENTION According to the present invention I have now found that the foaming characteristics of an aqueous solution of a detergent composition containing a nonionic surface active agent which is suitable for use for automatic dishwashing machines are substantially reduced by incorporating into said detergent the ethoxylate phosphate esters produced from alcohols containing from about 16 to 20 carbon atoms, l-mole ethoxylate blends of same, ethylene oxide adducts of 16 to 20 carbon alcohols, their blends, an alcohol-l-mole ethoxylate mixture, or a blend of ethylene oxide adducts of C to C alcohols wherein the l-mole adduct is optimized. Further, I have found that in order to obtain the desirable results of producing the low foam detergent composition suitable for use in automatic dishwashing machines, the phosphate ester of said ethoxylated alcohols employed in said detergent composition is present in the amount of about 0.05 to 2 weight percent, based on the total weight of said detergent composition. Especially desirable results are obtained where the phosphate ester additive is present in the amount of about 0.06 to about 0.5 weight percent, based on the total weight of the dishwashing detergent composition, and the weight ratio of phosphate ester additive to nonionic compound is about 1:20 to 1:5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The nonionic surface active agents which are advantageously employed in automatic dishwashing machine detergent compositions are generally the polyoxylkylene adducts of hydrophobic bases wherein the oxygen/ carbon atom ratio in the oxyalkylene portion of the molecule is greater than 0.40. Those compositions which are condensed with hydrophobic bases to provide a polyoxylkylene portion having an oxygen/carbon atom ratio greater than 0.40 include ethylene oxide, butadiene dioxide and glycidol, mixtures of these alkylene oxides with each other and with minor amounts of propylene oxide, butylene oxide, amylene oxide, styrene oxide, and other higher molecular weight alkylene oxides. Ethylene oxide, for example, is condensed with the hydrophobic base in an amount sufficient to impart water dispersibility or solubility and surface active properties to the molecule being prepared. The exact amount of ethylene oxide condensed with the hydrophobic base will depend upon the chemical characteristics of the base employed and is readily apparent to those of ordinary skill in the art relating to the synthesis of oxyalkylene surfactant condensates.

Typical hydrophobic bases which can be condensed with ethylene oxide in order to prepare nonionic surface active agents include monoand polyalkyl phenols, polyoxypropylene condensed with a base having from about 1 to 6 carbon atoms and at least one reactive hydrogen atom, fatty acids, fatty amines, fatty amides and fatty alcohols. The hydrocarbon ethers such as the benzyl or lower alkyl ether of the polyoxyethylene surfactant condensates are also advantageously employed in the compositions of the invention.

Among the suitable nonionic surfactants are the polyoxyethylene condensates of alkyl phenols having from about 6 to 20 carbon atoms in the alkyl portion and from about 5 to 30 ethenoxy groups in the polyoxyethylene radical. The alkyl substituent on the aromatic nucleus may be octyl, diamyl, n-dodecyl, polymerized propylene such as propylene tetramer and trimer, isooctyl, nonyl,

etc. The benzyl ethers of the polyoxyethylene condensates of monoalkyl phenols impart good properties to the compositions of the invention, and a typical product corresponds to the formula:

Higher polyalkyl oxyethylated phenols corresponding to the formula:

wherein R is hydrogen or an alkyl radical having from about 1 to 12 carbon atoms, R and R are alkyl radicals having from about 6 to 16 carbon atoms an n has a value from about 10 to 40, are also suitable as nonionic surfactants. A typical oxyethylated polyalkyl phenol is dinonyl phenol condensed with 14 moles of ethylene oxide.

Other suitable nonionic surface active agents are cogeneric mixtures of conjugated polyoxyalkylene compounds containing in their structure at least one hydrophobic oxyalkylene chain in which the oxygen/carbon atom ratio does not exceed 0.40 and at least one hydrophilic oxyalkylene chain in which the oxygen/ carbon atom ratio is greater than 0.40.

Polymers of oxyalkylene groups obtained from propylene oxide, butylene oxide, amylene oxide, styrene oxide, mixtures of such oxyalkylene groups with each other and with minor amounts of polyoxyalkylene groups obtained from ethylene oxide, butadiene dioxide, and glycidol are illustrative of hydrophobic oxyalkylene chains having an oxygen/ carbon atom ratio not exceeding 0.40. Polymers of oxyalkylene groups obtained from ethylene oxide, butadiene dioxide, glycidol, mixtures of such oxyalkylene groups with each other and with minor amounts of oxyalkylene groups obtained from propylene oxide, butylene oxide, amylene oxide and styrene oxide are illustrative of hydrophilic oxyalkylene chains having an oxygen/ carbon atom ratio greater than 0.40.

Among the conjugated polyoxylalkylene compounds which can be used in the compositions of the invention are those which correspond to the formula:

wherein Y is the residue of organic compound having from about 1 to 6 carbon atoms and one reactive hydrogen atom, n has an average value of at least about 6.4 as determined by hydroxyl number and in has a value such that the oxyethylene portion constitutes about 10 to 90 weight percent of the molecule. These surface active agents are more particularly described in US. Pat. No. 2,677,700.

Other conjugated polyoxyalkylene surface active agents which are most advantageously used in the compositions of the invention correspond to the formula:

wherein Y is the residue of an organic compound having from about 2 to 6 carbon atoms and containing x reactive hydrogen atoms in which x has a value of at least about 2, n has a value such that the molecular weight of the polyoxypropylene hydrophobic base is at least about 900 and m has a value such that the oxyethylene content of the molecule is from about 10 to 90 weight percent. Compounds falling within the scope of the definition for Y include, for example propylene glycol, glycerine, pentaerythritol, trimethylolpropane, ethylene, diamine and the like. As already noted, the oxypropylene chain, optionally, but advantageously, contain small amounts of ethylene oxide and the oxyethylene chains also optionally, but advantageously, contain small amounts of alkylene oxides such as propylene oxide and butylene oxide. These 4 compositions are more particularly described in US. Pat. No. 2,674,619. Additional conjugated polyoxyalkylene surface active agents which are advantageously used in the compositions of this invention correspond to the formula:

wherein P is the residue of an organic compound having from about 8 to 18 carbon atoms and containing x reactive hydrogen atoms in which x has a 'value of 1 or 2, n has a value such that the molecular Weight of the poly oxypropylene portion is at least about 58 and m has a value such that the oxyethylene content of the molecule is from about 10 to weight percent and the formula:

wherein P is the residue of an organic compound having from about 8 to 11 carbon atoms and containing x reactive hydrogen atoms in which x has a value of 1 or 2, n has a value such that the molecular weight of the polyoxyethylene portion is at least about 44 and m has a value such that the oxypropylene content of the molecule is from about 10 to 90 weight percent. In either case the oxypropylene chains may contain optionally, but advantageously, small amounts of ethylene oxide and the oxyethylene chains may contain also optionally, but advantageously, small amounts of alkylene oxide such as propylene oxide, butylene oxide and higher alkylene oxides containing 8 to 18 carbon atoms in the alkyl chains.

Thus, cogeneric mixtures of conjugated polyoxyalkylene compounds containing in their structure the residue of an active hydrogen-containing compound and at least one hydrophobic chain of units selected from the group consisting of oxypropylene and oxypropylene-oxyethylene units in which the oxygen-carbon atom ratio does not exceed 0.40 and at least one hydrophilic chain of units selected from the group consisting of oxyethylene and oxyethylene-oxypropylene units in which the oxygen/carbon atom ratio is greater than 0.40 are suitable nonionic surface active agents.

Further suitable nonionic surface active agents are the polyoxyethylene esters of higher fatty acids having from about 8 to 22 carbon atoms in the acyl group and from about 8 to 30 ethenoxy units in the oxyethylene portion. Typical products are the polyoxyethylene adducts of tall oil, rosin acids, lauric, stearic and oleic acids and the like. Additional nonionic surface active agents are the polyoxyethylene condensates of higher fatty acid amines and amides having from about 8 to 22 carbon atoms in the fatty alkyl or acyl group and about 10 to 30 ethenoxy units in the oxyethylene portion. Illustrative products are coconut oil fatty acid amines and amides condensed with about 10 to 30 moles of ethylene oxide.

Other suitable polyoxyalkylene nonionic surface active agents are the alkylene oxide adducts of higher aliphatic alcohols and thioalcohols having from about 8 to 22 carbon atoms in the aliphatic portion and about 3 to 50 oxyalkylene units in the oxyalkylene portion. Typical products are synthetic fatty alcohols, such as n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-hexadecyl, n-octadecyl and mixtures thereof condensed with 3 to 50 moles of ethylene oxide, a mixture of normal fatty alcohols condensed with 8 to 20 moles of ethylene oxide and capped with benzyl halide or an alkyl halide, a mixture of normal fatty alcohols condensed with 10 to 30 moles of a mixture of ethylene and propylene oxides, a mixture of several fatty alcohols condensed sequentially with 2 to 20 moles of ethylene oxide and 3 to 10 moles of propylene oxide, in either order; or a mixture of normal fatty alcohols condensed with a mixture of propylene and ethylene oxides, in which the oxygen/carbon atom ratio is less than 0.40, followed by a mixture of propylene and ethylene oxides in which the oxygen/carbon atom ratio is greater than 0.40, or a linear secondary alcohol condensed with 3 to 30 moles of ethylene oxide, or a linear secondary alcohol condensed with a mixture of propylene and ethylene oxides, or a linear secondary alcohol condensed with a mixture of ethylene, propylene, and higher alkylene oxides.

While any of the above list of nonionic surface active agents can be employed in automatic dishwashing machine detergent compositions, I have found particularly desirable results can be obtained wherein the nonionic compound is in the form of an alkyl polyethoxyethanol which is condensed with butylene oxide, thereby forming a nonionic surfactant having the general formula:

where R is a C to C alkyl group, It indicates a range of integers representing the statistical distribution of oxyethylene units obtained by condensing from about 3.5 to 10 moles of ethylene oxide with 1 mole of the compound providing said hydrocarbon groups, namely a higher aliphatic mono-alcohol, and x indicates a range of integers from about 0.5 to 1.5. Especially desirable results have been obtained wherein the butylene oxide capped nonionic employed has a R value which is a mixture of C and C alkyl groups, n has an average value in the range of 5 to 6, and x has an average value in the range of 0.75 to 1.25.

The phosphate ester additive which is used as the foam depressant in the detergent composition containing any of the above listed nonionic surface active agents and which are suitable for use in automatic dishwashing machines is produced by phosphorylation of a C to C linear alcohol, the l-mole ethoxylate of a C to C linear alcohol, blends of the ethoxylates of said alcohols, an alcoholl-mole ethoxylate mixture or a blend of ethylene oxide adducts of a C to C alcohol wherein the l-mole adduct is optimized. The phosphate ester can be either the acid or neutral (salt) form. When the neutral form is employed, any suitable alkali material, such as NaOH, KOH, NH OH, Na CO substituted ammonium compounds, such as mono-, di-, and tri-ethanol amines, and the like, can be used.

The l-mole ethoxylate constituent of the C to C alcohol can be prepared by distillation of a conventional ethoxylate in order to obtain the desired l-mole adduct, or it may be prepared by any of the known reactions, such as with sodium alcoholate or bromoethanol. Desirable results have been obtained wherein the l-mole ethoxylate of the C to C alcohol is prepared by either base or acid catalyzed ethoxylation of a primary C to C straight chain alcohol. Especially desirable results have been obtained by employing the acid catalyzed ethoxylation of the primary C to C straight chain alcohol because the acid catalyzed ethoxylation gives a poisson distribution of adducts which contains more of the desired l-mole adduct than does the base catalyzed ethoxylation which gives a wide distribution of adducts. However, it should be stressed that any method of obtaining the l-mole adduct for subsequent phosphorylation to produce the desired organic phosphate esters of the present invention can be employed.

The organic phosphate esters which are employed as the foam depressant in the detergent composition of the present invention can be prepared by any conventional phosphorylation method which is known in the art. For example, the organic phosphate ester additives of the present invention can be prepared by using 115 percent polyphosphoric acid at a mole ratio of 2:1 of the ethoxylate, the alcohol, or the alcohol-ethoxylate mixture to P The acid ester thus formed is preferred, although a neutral form is also effective.

The phosphate ester additives which, when incorporated with low foam nonionics, produce a detergent composition having suppressed foam properties in the presence of proteinaceous soil, is selected from the group consisting of the phosphate esters of C to C linear primary alcohols, the l-mole ethoxylate of the C to C alcohols, blends of the l-mole ethoxylate of said alcohols, a C to C alcohol-l-mole ethoxylate mixture, or a blend of ethylene oxide adducts of a C to C alcohol wherein the l-mole adduct is optimized. Evidence establishing the cirticality of the l-mole ethoxylate adduct will be clearly indicated in the examples to follow. Further, runs similar to those in the examples were conducted wherein the phosphate ester additives were produced from a primary C straight chain alcohol. However, in the case of the l-mole ethoxylate adducts of the C alcohol, the results were undesirable, showing that C products are not effective defoamers. However, when employing the C to C l-mole ethoxylate adduct, desirable results were obtained. The following data will further illustrate that phosphate esters prepared from a C to C alcohol or from the l-mole ethoxylate adduct is a good defoamer when employing the C to C range of alcohols, whereas the 2-mole ethoxylate adduct and higher of the same range of the C to C alcohols do not function as good defoamers. Especially desirable results were obtained when the phosphate esters were prepared from a linear C primary alcohol, a l-mole ethylene oxide adduct of a linear C primary alcohol, and a blend of ethylene oxide adducts of a linear C primary alcohol wherein the l-mole adduct is optimized.

To further illustrate the best manner contemplated for carrying out the invention, the following working examples are set forth. As indicated, the examples are primarily given by Way of illustration, and accordingly any enumeration of details set forth therein are not to be interpreted as a limitation on the invention as such limitations are indicated in the appended claims. All parts are parts by weight unless otherwise stated.

Example l.-A series of organic phosphate esters were prepared by conventional phosphorylation methods using 115% polyphosphoric acid at a mole ratio of 2:1 alcohol or ethoxylate to P 0 In the preparation of the organic phosphate esters, two (2) moles of the alcohol or ethoxylate were heated and stirred at 115 C. for minutes with one (1) mole of polyphosphoric acid. A nitrogen blanket was maintained on the system, while above ambient temperatures were maintained. At the end of the reaction period, a portion of each reaction product was neutralized with NaOH solution so that the products could be tested in both the acid and neutralized salt form.

Testing of the organic phosphate esters as an additive for low foam nonionics was done in an automatic dishwasher detergent formulation having the following composition:

Percent "ALFONIC LF and organic phosphate ester blend 2.9 Chlorinated trisodium phosphate 51.8 Sodium metasilicate v 19.9 Sodium carbonate 0.7 H 0 q.s.

The ALFONIC LF and phosphate ester blends used were 90-95% ALFONIC LF and 10-5% phosphate ester in both the acid and neutralized salt form (e.g., the detergent formulations contained from about 0.29 to 0.15 weight percent phosphate ester). The ALFON'IC LF nonionic employed is a low foam nonionic produced from a blend of C and C linear primary alcohols which have been ethoxylated with about 5.6 moles of ethylene oxide and capped with 0.95 mole of 1,2-butylene oxide.

The above described automatic dishwasher detergent formulation was then employed in a dishwasher test. The dish washing test consisted of stacking 1O clean plates in the dishwasher rack, filling the dishwasher to a measured level with l50- 5 F. condensate water containing essentially zero hardness. Fifty (50) grams of well-mixed whole egg and 25.6 grams of the detergent formulation was added to the water. The machine Was started and the rotor arm r.p.m.s were visually counted through the Plexiglas window in the door. The r.p.m.s were read for one minute each at 2, 4, 6, and 8 minutes. The values were then averaged for the four readings, and the average value is recorded in the table below. Because foam impedes the revolution of the rotor arm, a low r.p.m. value represents poor defoamiug, while a high rpm. value represents good defoaming.

In addition to the phosphate esters prepared from alcohols and standard base catalyzed ethoxylates, two phosphate esters were prepared from distillation cuts of a C ethoxylate. The composition of the cuts as determined by GLC were:

Weight percent adduct C high 1 EO C10 high 2 E 11. 6 1. 1 68. 7 23. 9 19. 1 75. 0 G rl-3 E O O. 6

Average r.p.m.

5% 10% Phosphate ester form acid acid Na salt Na salt Alkyl structure of phosphate structure:

38. 2 34. 2 36. 6 36. 6 31. 6 36.0 20.3 28. 5 Cm+2 mole avg. E0. 24. 9 32. 4 17.0 23. 4 Cm+3 mole avg. E0. 12. 5 26.8 14. 2 17.2 C1 high 1 mole EO.... 27. 6 32.0 27.4 31. 3 Cu high 2 mole E0 15.1 23. 9 13. 1 23. 1 C1 alcohol 32. 9 33. 6 28. 5 34. 3 C1 +1 mole avg. E0. 30. 5 32. 6 23. 6 29. 5 C1a+2 IIlO t avg. E0. 26. 6 29. 6 20. 5 24. 6 C1s+3 mole avg. E0. 21. 4 20.8 15.6 22.0 Cm-i-l mole avg. E0. 22. 4 31. 2 23. 5 28. 7 02 4-2 mole avg. E0... 19. 2 31. 9 18. 6 21.4 C2o+3 mole avg. E0 15.0 22. 7 14v 6 18.0 None 13. 5 13. 5 13. 5 13. 5

The above data clearly indicate the foaming properties of both the acid and Na salt form of phosphate esters formed from G -C alcohols and the 1 mole ethylene oxide adduct of said alcohols.

Experiments were also run with similar C products. The results of such runs were poor, indicating that the C products are not effective defoamers.

Example 2.-A series of experiments were conducted wherein a mixture of 95% ALFONIC LF and 5% of a phosphate ester of the 1 mole ethylene oxide adduct of a blend of C to C straight chain primary alcohols were substituted for the nonionic component in five commercial automatic dishwasher detergents. In each case the formulation containing the ALFONIC LF and phosphate ester was better in defoaming than the corresponding commercial detergent. The experiments were conducted under the same conditions as those in Example 1, and the defoaming properties were determined in the same manner. The results of the experiments are set out below.

A B C D E The above C1618 blend contains weight percent C constituent and 35 weight percent C constituent. When employing such blends, the ratio of C to C constituents can vary. However, I prefer to maintain more than 50 weight percent C constituent in said blends.

The above data in Examples 1 and 2 clearly indicate that organic phosphate esters produced from the l-mole ethylene oxide adducts of 16 to 20 carbon alcohols, their blends, and an alcohol-ethoxylate blend containing an appreciable amount of the l-mole ethylene oxide adduct, when blended with a low foam nonionic compound, produces a low form detergent composition which effectively suppresses foam generated by proteinaceous soil or articles being cleaned in automatic dishwashing machines.

Having thus described the invention, I claim:

1. A low foaming additive composition for use in automatic dishwashing machine detergent formulations, said additive composition consisting essentially of:

(A) an acid or neutral phosphate ester produced from the reaction of concentrated phosphoric acid and the l-mole ethylene oxide adduct of a linear C primary alkanol; and

(B) a butylene oxide capped nonionic surface active agent having the formula where R is a mixture of linear C and C alkyl groups, n is 5 to 6 and x is 0.5 to 1.5; the weight ratio of said (A) component to said (B) component being about 1:20 to 1:5.

2. A low foaming automatic dishwashing machine detergent composition consisting essentially of:

2.9 percent by weight of the additive composition of claim 1; 51.8hpercent by weight of chlorinated trisodium phosp ate; 19.9 percent oby weight of sodium metasilicate; 0.7 percent by weight of sodium carbonate; and the balance water.

References Cited UNITED STATES PATENTS 3,523,902 8/1970 SChmolka 252137 3,382,176 5/1968 Jakobi et al. 25289 3,341,467 9/1967 Hwa 252--321 3,314,891 4/1967 Schmolka et al 252---89 LEON D. ROSDOL, Primary Examiner D. L. ALBRECHT, Assistant Examiner US. Cl. X.R. 

